JP2010168446A - Method for producing water-in-oil emulsion ink for stencil printing and water-in-oil emulsion ink for stencil printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing water-in-oil emulsion ink for stencil printing and water-in-oil emulsion ink for stencil printing which has such fixing strength on paper as to retain the color under friction and which early achieves dryness on paper. <P>SOLUTION: The method for producing a water-in-oil emulsion ink for stencil printing containing 10-90 mass% of an oil phase and 90-10 mass% of a water phase and containing an aluminum chelate, a resin, a higher fatty acid and a colorant includes: a dispersion step of dispersing the aluminum chelate, the resin and the colorant in the oil phase; a dilution step of diluting the oil phase; and an emulsification step of mixing and emulsifying the oil phase and the water phase, wherein the higher fatty acid is mixed in the oil phase at least after the dispersion step and before the emulsification step. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a water-in-oil emulsion ink for stencil printing, which has a fixing strength on paper with little color fading due to rubbing and realizes a dry state on paper at an early stage, and stencil printing produced by the production method The present invention relates to water-based emulsion ink.

  As a stencil printing method, a method is widely known in which a stencil printing base paper is used, and ink is moved from one side of the base paper to the other side through the perforated portion of the base paper, thereby printing on the surface of the substrate such as paper. It has been. In recent years, rotary stencil printing presses have become more automated with microcomputers and the like, and the operation has become simpler.

  However, the only drying methods for stencil printing are osmotic drying and evaporation drying, and since a reactive resin cannot be used so that the ink does not solidify on the printing press, the stability and on-paper have been improved. Various studies have been conducted for the purpose of improving the fixing strength and early drying.

For example, for the purpose of improving these characteristics, an emulsion ink to which a solid resin or the like is added has been proposed (see Patent Document 1). Also, emulsion inks for stencil printing containing a gelling agent have been proposed for the purpose of improving ink fixing properties (see Patent Document 2 and Patent Document 3).
However, with these conventional technologies, a certain degree of fixing strength can be obtained, but due to the large amount of ink transfer unique to stencil printing, it takes time to obtain touch-drying properties, and paper folding, cutting, and two-color printing In order to carry out the next process such as double-sided printing, there is a problem that a long drying time is required.

In addition, for example, a resin component having a free carboxylic acid group or a higher fatty acid in the oil phase, and a divalent or trivalent metal salt and a monovalent metal salt exhibiting alkalinity in the aqueous phase There has been proposed an emulsion ink for stencil printing containing: According to the invention of emulsion ink for stencil printing, emulsion ink for stencil printing with improved emulsion stability can be obtained (see Patent Document 4).
However, in the emulsion ink for stencil printing described in Patent Document 4, if a higher fatty acid is added in advance in the dispersion step, the oil phase viscosity is increased and accompanied by a decrease in the permeation rate on the paper. There is also a problem that it is difficult to obtain sufficient drying property at an early stage.
Accordingly, there is currently no satisfactory method for producing a water-in-oil emulsion ink for stencil printing excellent in early drying properties in addition to fixing strength on paper in a stencil printer.

JP-A-11-310740 Japanese Patent No. 3725921 JP-A-5-117564 Japanese Patent No. 3571233

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, the present invention relates to a method for producing a water-in-oil emulsion ink for stencil printing that has a fixing strength on paper with little color fading due to rubbing and realizes a dry state on paper at an early stage, and stencil printing produced by the production method. It is an object to provide a water-in-oil emulsion ink.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a result, contain 10 mass% to 90 mass% of an oil phase and 90 mass% to 10 mass% of an aqueous phase, and contain an aluminum chelate, a resin, and a higher fatty acid. In the water-in-oil emulsion ink for stencil printing, by adding the higher fatty acid in the dispersion step and adding it later, the fixing rate to the printing paper becomes 85% or more within 30 minutes after printing. And a method for producing a water-in-oil emulsion ink for stencil printing that achieves both high fixing strength and the present invention, the present invention has been completed.

The present invention is based on the above knowledge of the present inventor, and means for solving the above problems are as follows. That is,
<1> A water-in-oil emulsion ink for stencil printing comprising 10% by mass to 90% by mass of an oil phase and 90% by mass to 10% by mass of an aqueous phase, and containing an aluminum chelate, a resin, a higher fatty acid, and a colorant. In the production method, a dispersion step of dispersing the aluminum chelate, the resin, and the colorant in the oil phase, a dilution step of diluting the oil phase, and mixing and emulsifying the oil phase and the aqueous phase. An emulsifying step, and at least after the dispersing step and before the emulsifying step, the higher fatty acid is mixed with the oil phase, and a method for producing a water-in-oil emulsion ink for stencil printing, is there.
According to the method for producing a water-in-oil emulsion ink for stencil printing of <1>, the aluminum chelate, the resin, and the colorant are dispersed in an oil phase in the dispersion step, and the oil phase is dispersed in the dilution step. The oil phase and the aqueous phase are diluted and mixed and emulsified in the emulsification step, and at least after the dispersion step and before the emulsification step, the higher fatty acid is mixed with the oil phase, so after printing 30 Within a minute, a water-in-oil emulsion ink for stencil printing having a fixing rate on a printing paper of 85% or more is obtained.
The reason why the water-in-oil emulsion ink for stencil printing has such an action is that when the ink penetrates into paper, the residual functional group of the resin is cross-linked by an aluminum chelate and gelled, and a higher fatty acid is used. Is considered to be promoting. In addition, the gelled resin is adsorbed on multiple colorants, strengthening the aggregation of the colorants, and the resin adsorbed on the colorants is also adsorbed on the paper, contributing to the fixation of the colorant to the paper. It is possible that
However, if higher fatty acids are blended during the dispersion process during ink production, the varnish becomes extremely viscous due to the gelation reaction, making the emulsification process extremely difficult, and the ink after the emulsification process is also difficult. Since there is a problem that the viscosity becomes extremely high, higher fatty acids are not blended during the dispersion step, and are added before the emulsification step, thereby intentionally avoiding an unnecessary gelation reaction during ink production. As a result, the viscosity of the emulsion ink, which is highly printable by a stencil printing press, is maintained, the gelation reaction occurs only on the paper, the fixing power of the colorant is increased, and the early drying property can be realized. It is considered a thing.
In the present specification, the fixing rate is the residual image density after rubbing 10 times a MONO eraser (MONO: registered trademark, Dragonfly Pencil Co., Ltd.) with a strength of 9 N · cm using a clock meter, It means the percentage value divided by the printed image density before rubbing.
<2> The method for producing a water-in-oil emulsion ink for stencil printing according to <1>, wherein the content of the aluminum chelate is 4% by mass to 15% by mass with respect to the mass of the colorant.
<3> The method for producing a water-in-oil emulsion ink for stencil printing according to any one of <1> to <2>, wherein the content of the resin in the oil phase is 10% by mass to 30% by mass.
<4> The method for producing a water-in-oil emulsion ink for stencil printing according to any one of <1> to <3>, wherein the content of the higher fatty acid in the oil phase is 3% by mass to 15% by mass.
<5> A water-in-oil emulsion ink for stencil printing, which is produced by the method for producing a water-in-oil emulsion ink for stencil printing according to any one of <1> to <4>.

  According to the present invention, the conventional problems can be solved, and the present invention is a water-in-oil emulsion for stencil printing that has a fixing strength on paper with less color fading due to rubbing and realizes a dry state on paper at an early stage. An ink production method and a water-in-oil emulsion ink for stencil printing produced by the production method can be provided.

(Method for producing water-in-oil emulsion ink for stencil printing)
The method for producing a water-in-water emulsion ink for stencil printing of the present invention includes a dispersion step, a dilution step, and an emulsification step. Furthermore, other processes appropriately selected as necessary are included.
The water-in-oil emulsion ink for stencil printing comprises 10% by mass to 90% by mass of an oil phase and 90% by mass to 10% by mass of an aqueous phase, and contains an aluminum chelate, a resin, a higher fatty acid, and a colorant. contains.

  Hereinafter, after describing the production process of the water-in-oil emulsion ink for stencil printing, components added to the water-in-oil emulsion ink for stencil printing will be described.

-Dispersing process-
The said dispersion | distribution process is a process of disperse | distributing the said aluminum chelate, the said resin, and the said coloring agent to the said oil phase (oil component), You may disperse | distribute another component as needed.
Examples of other components to be dispersed in the dispersion step include a dispersion aid, an extender pigment, and wax. The extender pigment and the wax can be added using known means.
The dispersion method is not particularly limited and may be appropriately selected depending on the purpose.
The method of manufacturing by mixing each component and performing a dispersion process using dispersers, such as a 3 roll mill, etc. are mentioned.

In the dispersion step, as described above, the higher fatty acid is not added.
If the higher fatty acid is blended during the dispersion step, the varnish becomes extremely viscous due to the gelation reaction, making the treatment in the emulsification step extremely difficult, and the ink after the emulsification treatment is also extremely high. There is a problem of viscosity increase.

-Dilution process-
The dilution step is a step of diluting the oil phase.
The dilution method is not particularly limited and can be appropriately selected depending on the purpose.
Examples thereof include a method of producing the dispersion by mixing a small amount of a diluent obtained by mixing each component while stirring the dispersion with a stirrer.

  The addition of the higher fatty acid is not particularly limited as long as it is mixed with the oil phase after the dispersion step and before the emulsification step, but is preferably added in the dilution step. By adding it before the emulsification step without adding at the time of the dispersion step, unnecessary gelation reaction at the time of ink production is avoided. This also maintains the viscosity of the emulsion ink, which is highly printable by a stencil printing machine, causes a gelation reaction only on the paper to increase the fixing force of the colorant, and can realize early drying properties.

  In the dilution step, an oil component may be added as a diluent, and an emulsifier for emulsifying in the emulsification step described later is added to the diluent.

-Emulsification process-
The emulsification step is a step of mixing and emulsifying the oil phase and the aqueous phase.

--Mixed--
In the emulsion ink for stencil printing, the mixing ratio of the oil phase and the water phase is within the range of 10% by mass to 90% by mass of the oil phase and 90% by mass to 10% by mass of the water phase as described above. However, the oil phase is preferably in the range of 20% by mass to 50% by mass and the water phase of 50% by mass to 80% by mass.
When the mixing ratio of the oil phase is less than 10% by mass, the ink may not have sufficient ink shape retention. When it exceeds 90% by mass, the effect of physically forming a water-in-oil emulsion is obtained. May be insufficient.

--Emulsification process--
The emulsification method is not particularly limited and can be appropriately selected depending on the purpose. For example, the aqueous phase is gradually added to the prepared oil phase and emulsified in a known emulsifier. Can be mentioned.

  Specifically, for example, an emulsification tester ET-3A type (manufactured by Nikko Chemicals Co., Ltd.) is used, and while the oil phase is charged into the emulsification tester and stirred at a speed of 400 rpm, the water phase is gradually added. Can be added and emulsified to prepare an emulsion ink for stencil printing.

-Other processes-
There is no restriction | limiting in particular as said other process, According to the objective, it can select suitably, For example, the preparation process of the said water phase is mentioned. The constituent of the aqueous phase is not particularly limited and may be appropriately selected depending on the intended purpose. For example, water, water-soluble polymer, antiseptic / antifungal agent, anti-evaporating agent, anti-freezing agent, pH adjustment Agents, electrolytes, thickeners, rust inhibitors and the like.

-Preparation of aqueous phase-
There is no restriction | limiting in particular as a preparation method of the said water phase, According to the objective, it can select suitably, For example, each component may be added to water and what is necessary is just to stir and mix using a well-known stirrer etc.

-Oil phase-
The component in the oil phase is not particularly limited and may be appropriately selected according to the purpose. For example, the oil component, the colorant, the aluminum chelate as a colorant dispersant, the resin, the higher fatty acid. , Emulsifiers, extender pigments, waxes and the like. As these components, known components that do not inhibit the formation of an emulsion are used.

There is no restriction | limiting in particular as said resin, According to the objective, it can select suitably, For example,
Examples include rosin-modified phenolic resins and alkyd resins. These resins may be used alone or in combination of two or more.
The rosin-modified phenolic resin is not particularly limited, and examples thereof include KG-836, KG-846, KG-1829, KG-1804, KG-1808-1, tamanor 371, and tamanor 394 manufactured by Arakawa Chemical Co., Ltd. It is done.
Moreover, there is no restriction | limiting in particular as this alkyd resin, For example, the alkyd resin comprised from fats and oils, a polybasic acid, and a polyhydric alcohol can be mentioned.

  The fats and oils are not particularly limited, and examples thereof include non-drying oils, semi-drying oils, and fatty acids having an iodine value of 100 or less, such as coconut oil, palm oil, olive oil, castor oil, rice bran oil, and cottonseed oil. If the iodine value is 100 or less, drying oils such as soybean oil, linseed oil, and tung oil may be used in part.

  The polybasic acid is not particularly limited, and saturated polybasic acids such as phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid, tetrahydrophthalic acid, and maleic acid, maleic anhydride, fumaric acid. Examples thereof include unsaturated polybasic acids such as acid, itaconic acid and citraconic anhydride.

  Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, glycerin, trimethylolpropane, neopentyl glycol, diglycerin, triglycerin, and pentaerythritol. Slits, dipentaery slits, mannits, sorbits and the like can be mentioned.

The oil length of the alkyd resin is represented by mass% in the resin when the fatty acid in the fat is present as triglyceride.
The alkyd resin preferably has an oil length of 60 to 90 and an iodine value of 100 or less from the viewpoints of dispersion stability and clogging of the plate cylinder screen due to film formation.
The molecular weight of the alkyd resin is preferably less than 30,000, and more preferably 10,000 or less.
Further, the addition amount of the total resin in the oil phase is preferably 50% by mass or less, more preferably 2% by mass to 50% by mass, and more preferably 10% by mass to 30% by mass of the oil phase, from the cost of ink and printability. Is more preferable, and 15% by mass to 25% by mass is particularly preferable.
When the addition amount of the resin is less than 2% by mass, it is difficult to obtain the effects of early drying and high fixing strength in the present invention, and when it exceeds 50% by mass, the viscosity of the ink increases, This makes it difficult to produce ink from the plate, resulting in printability problems such as fading of characters and inability to perform uniform solid printing.

The dispersant is not particularly limited as long as it contains an aluminum chelate, and may be an alkylamine polymer compound, a styrene-maleic anhydride copolymer polymer compound, a polycarboxylic acid, as long as it does not inhibit the formation of an emulsion. Acid ester type polymer compound, aliphatic polycarboxylic acid, amine salt of polymer polyester, ester type anionic surfactant, long chain amine salt of high molecular weight polycarboxylic acid, long chain polyaminoamide and polymer acid polyester It may contain a resin having a pigment dispersing ability such as a salt, a polyamide-based compound, a phosphate ester-based surfactant, an alkyl sulfocarboxylate, an α-olefin sulfonate, a dioctyl sulfosuccinate, and an alkyd resin.
These dispersing agents may be used individually by 1 type, and may use 2 or more types together.
The amount of the aluminum chelate added is preferably 4% by mass to 15% by mass or less, more preferably 5% by mass to 15% by mass, and particularly preferably 6% by mass to 10% by mass with respect to the colorant mass.

The higher fatty acid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, oleic acid, isostearic acid, stearic acid, palmitic acid, linoleic acid, linolenic acid, lauric acid, behenic acid, ricinoleic acid , Oxy fatty acids, tall oil fatty acids and the like, higher fatty acids which are liquid at normal temperature are preferable, and oleic acid and isostearic acid are more preferable from the viewpoint of oxidation stability and cost.
In addition, the total amount of the higher fatty acid added in the oil phase is preferably 20% by mass or less, more preferably 3% by mass to 15% by mass, and more preferably 5% by mass to 10% by mass, based on the cost of the ink and printability. Mass% is particularly preferred.
If it is less than 3% by mass, it is difficult to obtain the effects of early drying and high fixing strength in the present invention. If it exceeds 20% by mass, the stability of the emulsion is deteriorated, and the ink is left on the printing press. Problems with printability such as loosening occur.

The colorant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include carbon black, titanium oxide; azo pigments, phthalocyanine pigments, nitroso pigments, nitro pigments, vat dye pigments. And mordant dye pigments, basic dye pigments, acidic dye pigments and natural dye pigments; oil-soluble dyes such as diazo dyes and anthraquinone dyes; and the like. These colorants may be used alone or in combination of two or more.
The addition amount of the colorant in the water-in-oil emulsion ink for stencil printing is preferably 2% by mass to 10% by mass.
If it is less than 2% by mass, the printing density will be insufficient, and if it exceeds 10% by mass, the printing density will not increase even if it is added more, which is disadvantageous in terms of cost.

  The oil component is not particularly limited and can be appropriately selected according to the purpose.For example, petroleum solvent, liquid paraffin, spindle oil, machine oil, mineral oil, linseed oil, tall oil, corn oil, Examples include olive oil, coconut oil, rapeseed oil, castor oil, dehydrated castor oil, vegetable oil such as soybean oil, esterified vegetable oil, and the like, but those having less aromatic components are preferable. Synthetic oils can also be used.

There is no restriction | limiting in particular as said petroleum-based solvent, Exxon's Isopar series (C, E, G, H, L, M, etc.) and Exol (D-30, D-40, D-80, D-110). , D-130, etc.), Nippon Oil's AF Solvent Series (4, 5, 6, 7), Mobil Petroleum's Genrex Series (55, 56, 57) Idemitsu Kosan Co., Ltd. 14, 18) and the like.
The mineral oil is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include various industrial solvents, motor oils, gear oils, light oils, kerosene, spindle oils, machine oils, paraffinic oils, naphthenic oils. System oil and the like.

  There is no restriction | limiting in particular as said paraffinic oil, A commercial item can be used, for example, the Gargo oil arctic series by Mobile Oil Co., Ltd., Nippon Oil Super Oil series by Nippon Oil Corporation, Idemitsu Kosan Co., Ltd. Diana process oil, Diana Fresia series, etc.

There is no restriction | limiting in particular as said naphthenic oil, The carbon content (CN) of the naphthene component by ring analysis is 30 mass% or more, and the carbon content (CA) of an aromatic component is 20 mass% or less. The carbon content (CP) of the paraffin component is preferably 55% by mass or less.
Examples of such naphthenic oils include Gargo Oil Arctic Oils 155 and 300ID manufactured by Mobil Oil, Gargo Oil Arctic Oil Light, Gargo Oil Arctic Oil C Heavy; Diana Process Oil manufactured by Idemitsu Kosan Co., Ltd. Diana Fresia series; Sansen Oil series manufactured by Sun Oil Co., Ltd.
These mineral oils may be used alone or in combination of two or more.

  The vegetable oil is not particularly limited and may be appropriately selected depending on the intended purpose.For example, soybean oil, corn oil, sunflower oil, rapeseed oil, safflower oil, sesame oil, castor oil, dehydrated castor oil, camellia oil, olive oil, Palm oil, rice oil, cottonseed oil, palm oil, linseed oil, palm kernel oil, tung oil, camellia oil, grape seed oil, sweet almond oil, pistachio nut oil, jojoba oil, macadamian nut oil, meadow home oil, etc. Can be mentioned. These may be used alone or in combination of two or more.

There is no restriction | limiting in particular as said esterified vegetable oil, For example, what esterified the said vegetable oil is mentioned. Moreover, there is no restriction | limiting in particular as said ester, For example, methyl ester, ethyl ester, butyl ester etc. are mentioned.
As the esterified vegetable oil, methyl esterified soybean oil is particularly preferable.

There is no restriction | limiting in particular as said emulsifier, Although it can select suitably according to the objective, A nonionic surfactant is preferable.
The nonionic surfactant is not particularly limited, and examples thereof include sorbitan higher fatty acid esters, polyoxyethylene sorbitan higher fatty acid esters, fatty acid monoglycerides, polyglycerin fatty acid esters, fatty acid diglycerides, and higher alcohols, alkylphenols, fatty acids and the like. And ethylene adducts. These may be used alone or in combination of two or more different HLBs to prepare a highly stable emulsion.
The addition amount of the emulsifier in the water-in-oil emulsion ink for stencil printing is usually 0.5% by mass to 15% by mass, but preferably 2% by mass to 5.5% by mass.
If it is less than 2% by mass, a stable emulsified state cannot be maintained, and if it exceeds 5.5% by mass, this cannot also maintain a stable emulsified state, and in terms of cost. It will be disadvantageous.
In addition to the above, a dispersion aid, an antioxidant and the like can be added to the oil phase as long as the formation of the emulsion is not inhibited.

-Water phase-
The component in the aqueous phase is not particularly limited and can be appropriately selected according to the purpose. Water, water-soluble polymer, antiseptic / antifungal agent, anti-evaporating agent, anti-freezing agent, pH adjusting agent, Examples include electrolytes, thickeners, and rust inhibitors. As these components, known components that do not inhibit the formation of an emulsion are used.

  There is no restriction | limiting in particular as said water, For example, ion-exchange water is mentioned.

The water-soluble polymer is added for moisturizing and thickening, and specifically, the following natural or synthetic polymers are added.
For example, natural polymers such as starch, mannan, sodium alginate, galactan, tragacanth gum, gum arabic, pullulan, dextran, xanthan gum, glue, gelatin, collagen, casein; carboxymethylcellulose, hydroxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, Semi-synthetic polymers such as hydroxymethyl starch, carboxymethyl starch, and dialdehyde starch; neutralized products such as acrylic resin and sodium polyacrylate; polyvinyl imide, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, poly N-alkyl Substituted acrylamide, polyethylene oxide, polyvinyl methyl ether, styrene-maleic anhydride copolymer Styrene - acrylic acid copolymer, and a polymer thereof were partially hydrophobic alkyl group also include acrylamide-based polymers and acrylic polymers. The acrylamide polymer and the acrylic polymer may be a copolymer type polymer in which a substituent is partially hydrophobized with an alkyl group.
A block copolymer of polyethylene and polypropylene or polybutylene can also be used.
These water-soluble polymers may be used alone or in combination of two or more.
Although there is no restriction | limiting in particular as the addition amount in the water phase of the said water-soluble polymer, 25 mass% or less is preferable, and 0.5 mass%-15 mass% are more preferable.
If the amount is less than 0.5% by mass, the intended effect cannot be sufficiently obtained. If the amount exceeds 25% by mass, the viscosity on the paper may be excessively increased and the drying property of the ink on paper may be lowered.

  There is no restriction | limiting in particular as said oil-in-water type resin emulsion, According to the objective, it can select suitably, For example, a synthetic polymer may be sufficient and a natural polymer may be sufficient.

The synthetic polymer is not particularly limited. For example, polyvinyl acetate, polyacrylate ester, polymethacrylate ester, polyvinyl chloride, ethylene-vinyl acetate copolymer, vinyl acetate-acrylate copolymer, Examples thereof include styrene-acrylic acid ester copolymers, vinylidene chloride-acrylic acid ester copolymers, vinyl chloride-vinyl acetate copolymers, and polyurethanes.
There is no restriction | limiting in particular as said natural polymer, The said polymer etc. which can be added to the said oil phase are mentioned.
These may be used in combination of two or more as long as they do not impair the stability of the water-in-oil emulsion ink for stencil printing, and are dispersed by adding a dispersant, a protective colloid, and a surfactant. It may be prepared, or may be synthesized by soap-free emulsion polymerization.

The antiseptic / antifungal agent is added to prevent bacteria and fungi from growing in the emulsion, and is added when the emulsion ink is stored for a long period of time.
Although there is no restriction | limiting in particular as the addition amount in the said water of the said antiseptic / fungicide, 3 mass% or less is preferable, and 0.1 mass%-1.2 mass% are more preferable.
If it is less than 0.1% by mass, the intended effect cannot be sufficiently obtained, and if it exceeds 3% by mass, a stable emulsified state may not be maintained.

  Further, the antiseptic / antifungal agent is not particularly limited. For example, in addition to aromatic hydroxy compounds such as salicylic acid, phenols, methyl p-oxybenzoate, ethyl p-oxybenzoate, and chlorine compounds thereof, isothiazoline Compounds, triazine compounds and pyridine compounds, sorbic acid, dehydroacetic acid and the like. These may be used alone or in combination of two or more.

The anti-evaporating agent and the anti-freezing agent can be used in combination, and are added for the purpose of preventing evaporation and anti-freezing.
The evaporation inhibitor and the antifreeze agent are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include glycols such as ethylene glycol, diethylene glycol and propylene glycol; methanol, ethanol, isopropanol, butanol, isopropanol Lower saturated monohydric alcohols such as butanol; polyhydric alcohols such as glycerin and sorbitol; and the like. These may be used alone or in combination of two or more.
There is no restriction | limiting in particular as the addition amount in the said water as a total amount of the said evaporation inhibitor and the said antifreezing agent, 15 mass% or less is preferable, and 4 mass%-12 mass% are preferable.
If the amount is less than 4% by mass, the intended effect cannot be sufficiently obtained. If the amount exceeds 15% by mass, the intended effect is not increased if the amount is more than that amount, which is disadvantageous in terms of cost.

The pH adjuster is added for the purpose of adjusting the pH of the aqueous phase. The pH of the aqueous phase is preferably 6-8. When the pH deviates from the above range, there is a problem that the effect is impaired when the water-soluble polymer for thickener is added.
There is no restriction | limiting in particular as said pH adjuster, For example, a triethanolamine, sodium acetate, a triamylamine etc. are mentioned.

The electrolyte is added to increase the stability of the emulsion ink. Therefore, it is preferable to add an electrolyte composed of ions having a high liquid separation permutation effective for improving the stability of the emulsion.
Anions having a high liquid separation permutation are citrate ions, tartaric acid ions, sulfate ions, acetate ions, etc., and cations having a high liquid separation permutation are alkali metal ions and alkaline earth metal ions. The electrolyte added here is preferably a salt in which at least one of an anion and a cation is composed of the ion.
Such an electrolyte is not particularly limited, but for example, magnesium sulfate, sodium sulfate, sodium citrate, sodium hydrogen phosphate, sodium borate, sodium acetate, and the like are preferable.
There is no restriction | limiting in particular as the addition amount in the aqueous phase of the said electrolyte, 0.1 mass%-2 mass% are preferable, and 0.2 mass%-1 mass% are more preferable.
If it is less than 0.1% by mass, the intended effect cannot be sufficiently obtained, and if it exceeds 2% by mass, a stable emulsified state may not be maintained.

-Other ingredients-
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, an extender, a wax, a thickener, a rust preventive agent etc. are mentioned.

The extender pigment is added to prevent bleeding of the water-in-oil emulsion ink for stencil printing and to adjust the viscosity.
The extender pigment is not particularly limited, and examples thereof include white clay, silica, talc, clay, calcium carbonate, barium sulfate, titanium oxide, alumina white, diatomaceous earth, kaolin, mica, and aluminum hydroxide, and polyacrylic. Examples thereof include organic fine particles such as acid ester, polyurethane, polyester, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polysiloxane, phenol resin, and epoxy resin, or fine particles made of a copolymer thereof.
Specific examples include, for example, Aerosil 200, Aerosil R972 (Nippon Aerosil Co., Ltd.), NEW D ORBEN (Shiraishi Kogyo Co., Ltd.), BEN-GEL, S-BEN, ORGANITE (Toyokawa Yoko Co., Ltd.), TIXOGEL series (VP) , DS, GB, VG, EZ-100, etc.), OPTIGEL (Nissan Gardler).
These may be added to the oil phase, the aqueous phase, or both phases.
There is no restriction | limiting in particular as the addition amount in the water-in-oil emulsion ink for stencil printing of the said extender, 0.01 mass%-50 mass% are preferable, and 0.1 mass%-10 mass% are more preferable.
If it is less than 0.01% by mass, the intended effect cannot be sufficiently obtained, and if it exceeds 50% by mass, a stable emulsified state may not be maintained.

The wax is added to the oil phase in order to improve the separation between the printing paper and the printing drum during printing or to prevent the printing paper from rolling up.
The thickener is added to the aqueous phase in order to further increase the viscosity by adding a water-soluble polymer.
There is no restriction | limiting in particular as said thickener, For example, a triethanolamine, sodium hydroxide, etc. are mentioned.
The rust preventive is added to the aqueous phase in order to prevent the printing press from being rusted by ink or causing ink to foam during printing.
There is no restriction | limiting in particular as said rust preventive agent, According to the objective, it can select suitably.
As the wax, the thickening agent, and the rust preventive agent, a known product added to the stencil printing ink may be added as necessary, and the addition amount is about the same as that of the conventional product. Good.

The viscosity of the water-in-oil emulsion ink for stencil printing produced in this way can be adjusted by the stirring conditions, but the viscosity at a shear rate of 20 s ^-1 is 10 Pa · s to 35 Pa · s. That's fine. The viscosity of the oil phase at a shear rate of 20 s ⁻¹ when a pigment, resin, extender pigment or the like is added to the oil phase is 0.05 Pa · s to 20 Pa · s, preferably 0.1 Pa · s to 3 Pa · s. It is desirable that s.

(Water-in-oil emulsion ink for stencil printing)
The water-in-oil emulsion ink for stencil printing of the present invention is manufactured by the method for producing the water-in-oil emulsion ink for stencil printing of the present invention, and the water-in-oil emulsion for stencil printing of the present invention. All the matters described as the ink production method can be applied.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples. In addition, the addition amount of the composition in the water-in-oil emulsion ink for stencil printing in Examples and Comparative Examples indicates the addition amount when the total amount of each composition is 1,000 parts by mass.

Example 1
-Dispersing process-
Of the compositions shown in Table 1 below, 54 parts by mass of an oil component (SUNTHEN 380, manufactured by Nippon San Oil Co., Ltd.), 6 parts by mass of a dispersant (Plenact AL-M, manufactured by Ajinomoto Fine-Techno Co., Ltd.), and a dispersion aid (Azisper PN411) 12 parts by mass of Ajinomoto Fine Techno Co., Ltd., and 40 parts by mass of rosin-modified phenolic resin (KG-846, Arakawa Chemical Co., Ltd.) and 40 parts by mass of soybean oil-modified alkyd resin (Arachid 251, Arakawa Chemical Co., Ltd.) And 72 parts by mass of a colorant (RAVEN 1100, manufactured by Columbia Carbon Co., Ltd.) were mixed and then kneaded by a three roll mill apparatus (manufactured by Inoue Seisakusho Co., Ltd.) to prepare these dispersions.

-Dilution process-
Of the compositions shown in Table 1 below, as oil components, 50 parts by mass of soybean methyl ester (Vertecbio Gold # 4, manufactured by Vertec Biosolvents) and 36 parts by mass of α-olefin oil (Linearene 18, manufactured by Idemitsu Kosan Co., Ltd.) A diluted solution was prepared by mixing 30 parts by mass of a fatty acid (oleic acid, manufactured by Kanto Chemical Co., Inc.) and 36 parts by mass of an emulsifier (Crill 4, manufactured by Croda).
This diluted liquid and the dispersion prepared in the dispersion step were mixed to prepare a diluted oil phase.

-Emulsification process-
The diluted oil phase was stirred with a stirrer to prepare an oil phase.
Moreover, among the compositions shown in Table 1 below, 524 parts by mass of water (ion-exchanged water), 43.5 parts by mass of an antifreezing agent (glycerin, manufactured by NOF Corporation), water-soluble resin PVP (Luvitec K-30 30% aq) 49.5 parts by mass of BASF) and 3 parts by mass of electrolyte (magnesium sulfate (7 hydrate), manufactured by Kanto Chemical Co., Ltd.) were mixed to prepare an aqueous phase.
The oil phase was charged into an emulsification tester ET-3A type (manufactured by Nikko Chemicals Co., Ltd.), and the water phase was gradually added and emulsified while stirring at a speed of 400 rpm. A water-in-water emulsion ink was produced.

(Examples 2-3)
In Example 1, the water-in-oil emulsion ink for stencil printing of Examples 2 to 3 was produced in the same manner as in Example 1 except that the addition amount of each composition was changed to the addition amount shown in Table 1. did.

(Comparative Examples 1-7)
In Example 1, the water-in-oil emulsion ink for stencil printing of Comparative Examples 1 to 7 was produced in the same manner as in Example 1 except that the addition amount of each composition was changed to the addition amount shown in Table 1. did.
(Comparative Example 8)
In Example 1, a water-in-oil emulsion ink for stencil printing of Comparative Example 8 was used in the same manner as in Example 1 except that higher fatty acid was added in the dispersion step instead of adding higher fatty acid in the dilution step. Manufactured.

<Measurement of fixing rate>
The fixing rate (%) was calculated by the following formula using a printing density (Id) and a residual density (Id) described later.
Formula: (residual density / print density) × 100 (%)

<Measurement of printing density>
Using the water-in-oil emulsion ink for stencil printing of Examples 1 to 3 and Comparative Examples 1 to 8, sufficiently pre-printed with a commercially available Ricoh Co., Ltd. stencil printing machine (Saterio A650), and the ink in the printing press And then printed on Ricoh fine paper (T6200). Thereafter, the print image density after 30 minutes and 60 minutes was measured with a reflection optical densitometer (RD914 manufactured by Macbeth).

<Measurement of residual concentration>
Using a clock meter (manufactured by Toyo Seiki Co., Ltd.), the MONO eraser (MONO: registered trademark, Dragonfly Pencil Co., Ltd.) is rubbed back and forth 10 times with a clock meter (manufactured by Toyo Seiki Co., Ltd.). The thinned image density was measured using a reflection type optical densitometer (RD914, manufactured by Macbeth Co., Ltd.), and used as the residual density.

<Evaluation of printability>
Evaluation of printability is to confirm the presence or absence of mechanical problems in a state where each manufactured emulsion ink is filled in a commercially available Ricoh stencil printing press (Saterio A650).
In Comparative Examples 1 and 8, the viscosity of the emulsion ink is too high, the ink is not sufficiently supplied to the paper from the stencil printing base paper, and the solid image (the filled portion in the image formed on the paper) is not completely filled. The condition has been confirmed.
Further, in Comparative Example 6, after being left for 24 hours after printing, the low viscosity ink leaked from the edge of the printing base paper wound around the printing drum.

<Evaluation of fixing rate>
Based on the measurement result of the fixing rate, the fixing rate was evaluated according to the following criteria.
-Evaluation criteria-
○: The fixing rate after 30 minutes and after 60 minutes is 85% or more.
X: The fixing rate after 30 minutes and after 60 minutes is less than 85%.

<Comprehensive evaluation>
Based on the evaluation results of the printing suitability and the fixing rate, the following criteria were comprehensively evaluated.
-Evaluation criteria-
○: The problem is solved and no printability problem is found ×: The problem cannot be solved or there is a problem of printability

  From the results shown in Table 2, the water-in-oil emulsion ink for stencil printing produced by the method for producing a water-in-oil emulsion ink for stencil printing of the present invention has very high fixing strength on paper and early drying. I know that there is.

  The method for producing a water-in-oil emulsion ink for stencil printing and a water-in-oil emulsion ink for stencil printing according to the present invention can achieve both early drying and high fixing strength in printing paper after printing. It can be suitably used for stencil printing by various stencil printing machines.

Claims (5)

A method for producing a water-in-oil emulsion ink for stencil printing comprising 10 mass% to 90 mass% of an oil phase and 90 mass% to 10 mass% of an aqueous phase, and containing an aluminum chelate, a resin, a higher fatty acid, and a colorant In
A dispersion step of dispersing the aluminum chelate, the resin, and the colorant in the oil phase;
A dilution step for diluting the oil phase;
An emulsification step of mixing and emulsifying the oil phase and the aqueous phase,
A method for producing a water-in-oil emulsion ink for stencil printing, wherein the higher fatty acid is mixed with the oil phase at least after the dispersion step and before the emulsification step.   The method for producing a water-in-oil emulsion ink for stencil printing according to claim 1, wherein the content of the aluminum chelate is 4% by mass to 15% by mass with respect to the mass of the colorant.   The method for producing a water-in-oil emulsion ink for stencil printing according to any one of claims 1 to 2, wherein the content of the resin in the oil phase is 10% by mass to 30% by mass.   The method for producing a water-in-oil emulsion ink for stencil printing according to any one of claims 1 to 3, wherein the content of the higher fatty acid in the oil phase is 3% by mass to 15% by mass.   A water-in-oil emulsion ink for stencil printing, which is produced by the method for producing a water-in-oil emulsion ink for stencil printing according to any one of claims 1 to 4.